THE TWILIGHT ZONE EFFECT

Gyroscopic effect of flywheel energy storage

Compared with other ways to store electricity, FES systems have long lifetimes (lasting decades with little or no maintenance; full-cycle lifetimes quoted for flywheels range from in excess of 10 , up to 10 , cycles of use), high (100–130 W·h/kg, or 360–500 kJ/kg), and large maximum power output. The (ratio of energy out per energy in) of flywheels, also known as round-trip efficiency, can be as high as 90%. Typical capacities range from 3 to 1. Flywheel energy storage systems using mechanical bearings can lose 20% to 50% of their energy in two hours. Much of the friction responsible for this energy loss results from the flywheel changing orientation due to the rotation of the earth (an effect similar to that shown by a Foucault pendulum). [pdf]